EXHIBIT 99.1 CONSOL ENERGY INC. 1800 Washington Road Pittsburgh, Pennsylvania 15241 Certification of Principal Executive Officer Pursuant to 18 U.S.C. 1350 (Section 906 of the Sarbanes-Oxley Act of 2002) I, J. Brett Harvey, President and Chief Executive Officer (principal executive officer) of CONSOL Energy Inc. (the "Registrant"), certifies that to my knowledge, based upon a review of the Quarterly Report on Form 10-Q for the period ended September 30, 2002 of the Registrant (the "Report"): (1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and (2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Registrant. By: /s/ J. Brett Harvey --------------------------------- Name: J. Brett Harvey Date: November 11, 2002